1. Field of the Invention
The present invention relates to a noncontacting IC card system for use in exchanging data by using electromagnetic waves, and more particularly, a noncontacting IC card system applied to a gate facility using intermediate or long waves.
2. Description of the Related Art
FIG. 15 schematically illustrates a gate facility to which a known noncontacting IC card system is applied. In this figure, G1, G2 are gates, respectively. Denoted by numeral 1 is a user of the gate facility who carries a noncontacting IC card 20 and 2, 3 are gate partition plates, respectively. An antenna to be described later (see FIG. 16) is provided on each gate partition plate 2.
The user 1 advances, for example, in the direction from the reverse surface to the front surface of FIG. 15 within the gate G1 or G2. During this time period, communication is effected between an antenna located within the gate partition plate 2 and the carried noncontacting IC card (hereinafter referred to simply as a card) 20. Only if, as a result of such communication, the user 1 is determined as a person who has received permission for passage, the gate barrier (see FIG. 16) located on the foreside of FIG. 15 is opened so that the user 1 may advance further.
FIG. 16 is a top view of the gate facility as shown in FIG. 15. In this figure, denoted by numeral 10 is a transmitting/receiving antenna, and GB1 and GB2 are gate barriers, respectively. Further, included in this figure are: a communication area AB of the transmitting/receiving antenna occurring within the gate; a communication area X occurring outside the gate; a dead zone C provided to avoid an interference between the transmitting/receiving antennas 10 of the gates G1, G2; and D which indicates the traveling direction of a user.
FIG. 17 illustrates construction of the control system of a gate (G1 or G2). Included in this figure are: a controller 30 connected to the transmitting/receiving antenna 10; a host computer 40; and a gate barrier opening/closing control section 50. The controller 30 controls communication and processes data between the card 20 and the transmitting/receiving antenna 10. The result of processing is transmitted to the host computer 40. Then, the host computer 40, for example, provides a command for opening/closing the gate barrier GB1 or GB2 to the gate barrier opening/closing control section 50.
In some cases, as indicated by a broken line in FIG. 17, the controller 30 directly controls the gate barrier opening/closing control section 50 without the host computer 40. In such a case, the host computer 40 is not necessary.
In FIG. 16, when the user passes the gate in the traveling direction D, communication between the transmitting/receiving antenna 10 and the card 20 is effected and, for example, the controller 30 reads through the transmitting/receiving antenna 10 such information as an ID code and the balance of the card 20. Based on this, a decision is made as to whether the gate barrier GB1 or GB2 is to be opened or not.
In this type of system, since an electromagnetic wave output from the transmitting/receiving antenna 10 is more intense than that from the card 20, a cross talk between the two transmitting/receiving antennas 10 (reception by the transmitting/receiving antennas 10 of the gate G2 of the electromagnetic wave transmitted by the transmitting/receiving antenna 10 of the gate G1) results if a large dead zone C is not provided. Accordingly, it is necessary to provide a separation between gates. Further it is necessary to prevent a person carrying a card from entering the communication area X outside the gate, so as to avoid communication with the card outside the gate.
Since the known noncontacting IC card system is constructed as described, gates that are next to each other must be spaced from each other to provide a dead zone C. Further, the gate facility must be disposed so as to take into consideration that a person carrying the card should not be permitted into the unnecessary communication area X which occurs outside the gate. Problems thus occur as that a large area is occupied by the gate facility as a whole.